Resistance-control apparatus



July 24, 1928.

H. J. WIEGAND RESISTANCE CONTROL APPARATUS Filed July 18, 1923 INVENTOR 1H .WAW

' ATTORNEY Patented July 24,192

. UNITED PATENT OFFICE.

HENRY WIEGAND, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAH- MER MFG. 60., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

RESISTANCE-CONTROL APPARATUS.

Application filed July 18,

This invention relates to resistance con trol apparatus and while notlimited thereto is particularly applicable in conjunction with a suitable capacitance device or devices, as in controlling the current leakage of audion valves or the like.v

In such apparatus, wherein sensitive adjustment is very essential, it is necessary that the same be of absolute reliability, smooths and substantially noiseless in operation and capable of critical adjustment."- I

. The present invention has as an object that of providing resistance control apparatus for such and similar purposes exhibiting the foregoing characteristics.

Another object is that jof' providing resistance control ap aratus particularly applicable in cont'ro mg the current leakage and consequent potential of certain units of l an audion valve or the like, comprising simple andrdurable parts, compactly and conveniently arranged. l .n I

Another object is that of providing a resistance control device wherein provision is made for readily mounting the same with reference to a suitable panel or other sup- .port and also with reference to associated v instrumentalities.

, Another object is thatof 1providing a resistance control device whic provides ease and convenience of installation and reliability of o eration.

Other 0 jects and advantages will hereinafter appear,

In the accompanying drawing wherein is illustrated an embodiment which the invention may assume in practice;

Figure 1 is a side elevational view, partly in section thereof, while; Fig.2 is a rear elevational view of the same. y Referring to. the drawing and particularly to Fig. 1, the same illustrates a resistance control device com rising a supportin plate 5 of suitable ins ating material to h cured to a mounting'plate or panel 6 by securing means such as bolt 7. v I A resistance element 8is carried .by supporting plate 5, said resistance element preferably comprising a disc -9 of suitable insulating material, having the periphery of coated with a relat1ve1 narrow and .of graphite 10 or other suita le conductive matherea 1923. Serial No. 652,462.

terial. A saw cut or gap 11 (Fig. 2) is adapted to break the continuity of the conductlve coating.

Disc 9' is mounted upon a hub member 12 the latter being provided with an annular flange 13 against which the disc 9 is swaged,

'spun or otherwise rigidly held. A passage 14, preferably located adjacent said saw cut or the like serves to connect the periphery of the disc 9 with an"annular recess"15, theaxial depth of said recess being preferably less than the diameter of the passage 14. A connector 16 of relativelysoft conducting material such for example as fuse wire, and

preferably of a diameter greater than the axial depth. of recess 15 is inserted in the passage 14 and wrapped about hub member 12 within said recess 15, the arrangement will projet axially beyond the face of disc 9,said portion being forced and held against and in permanent electrical engagement with flange 13 during the mounting of the disc 9 and hub member '12 by swaging or otherwise as aforedescribed. The other terminal portion of said connector is preferably arranged to terminate substantially flush with the, periphery'of the-disc 9, being what to insure pe'rmanentand adequate contact with the graphite 10 on the periphery of the disc.

Hub member12 is provided with reduced terminal p0rtions'17 and 18 having shoulders 19 and 20associated therewith respectively. The hub terminal 7 ortion 17 is adapted to be inserted within a suitable opening in en portinglplate 5 to terminate substantially ush with the outer surface of the latter. A washer 21 is preferably interposed between said disc and saidsupportlngplate to ,provide for unhampered angular movementxof the former relative to the lat- ,being such that a portion of connector 16 p v preferably flattened and expanded some ter, said washer being strung upon the re-- I ducedaiterminal portion 17 of the hub 12 to. abut the shqulder 19.

A combined center terminal and supporting' member 22 preferabl com osed of resihent metal such as p osphor bronze is secured to'the supporting plate 5 as by'screw bolts 23. Said member 22 is provided with an off-set portion 24 having an a erture 25 to receive and provide a bearing or the .reduced portion 18 of hub member 12. In

assembling the disc 9 with respect to supporting plate the off-set portion 24 is sprung outwardly to permit insertion of the internal screw threads to receive a screw 27 the head of said screw being adapted to lock against the adjacent face of the reduced portion 18 of said hub for positively anchoring the screw to said hub and disc. Said screw is further. adapted to penetrate the supporting plate 5 and the panel 6, assuming the device to be panel mounted, and to receive therebeyond a suitable operating knob 28 which is locked to said screw in suitably spaced relation to the stationary parts in any desired or preferred manner, as by means of lock nut 29.

A stud 30 having a pedestal portion 31 and a screw portion 32 is riveted to the supporting plate 5, said pedestal portion having a through passage 33 to receive a brush 34 of graphite or other suitable materiaL-said brush being arranged to make contact with the periphery of disc 9. A spring clip 35 of resilient material is held in place by a nut 36 acting on screw portion 32 of said stud. Said clip is adapted to exert pressure on brush 34 thereby keeping the same in positive contact with the disc.

Upon rotation of the disc, by means of its operating knob aforedescribed, said brush is adapted to deposit upon'the periphery of the disc the aforementioned thin conductive coating comprising material of thebrush. Also the relative movement of the disc and brush incident to service is suf- I ficient to restore and maintain the coating against loss by abrasion or otherwise. In

practice the periphery of the disc is pref-- erably rounded or tapered axially, substantially as illustrated whereas the c0-operat-' brush.

The supporting member 22 is preferably extended beyond the region of attachment thereof to the supporting plate 5 and reflexed to provide, either directly or indirectly, a terminal support for one end of a suitable condenser or the like to be employed in conjunction with the resistance control apparatus aforedescribed.

The opposite end of such condenser or the like is preferably mechanicallysupported by and in electrical contact with the screw portion 32 of stud 30, said stud being preferably prolonged to provide a suitable joint terminal for such condenser and resistance control device.

In practice the first mentioned end of the condenser may be connected, as by aterminal stud, directly to the adjacent reflexed end of the supporting member 22, thereby obviously connecting the condenser and resistance control device electrically in the usual parallel relation to one another. However, preferably a slotted conductive link 37 is interposed between said adjacent ends of the condenser and'said supporting member for longitudinal and pivotal adjustability rela- I tive't-o'both, thereby adapting the device to practically any desired length or other di mension of the particular condenser or the like to be emplo ed.

In Fig. 2 is ilustrated an adaptation of the device to mounting in a relation of support solely by means of a single conductive terminal, sue for example as the grid terminal 38 of an audion tube socket. Thus a flexible jumper 39 may be mechanically anchored and electricallyconnected to the device as shown in Fig. 1, the free end of said jumper having an opening 40 to receive a suitable supporting terminal such as the terminal 38 of the tube socket 41, the entire device-being held in place by thumb nut 42. This method of mounting provides a very short lead to the grid of the audion valve thereby minimizing external influence upon the grid.

When the device is arranged for panel mounting as shown inFig. 1 the circuit may be traced from terminal 43 through the capacitance device 44 to terminal 45 and also in parallel with the former circuit from terminal 43 and pedestal portion 31, through brush 34 to that portion of the graphite coating on the periphery of disc 9 determined by the adjustable setting of same, through connector 16 to hub 12, through resilient member 22 and conductive link 37 to terminal 45. As shown in Fig. 2v the circuit will be identical with the aforedescribed with the exception that. flexible place of terminal 45.

umper 39 will function as a terminal in What I claim as new and by Letters Patent is:

1. In resistance control apparatus, in combihation, a circular element havin the periphery thereof coated with grap its, the periphery of said element being cut away at a given region to provide for interruption of 'said coating, a spring tensioned graphite brush, to coact with the peripheral portion of said element for maintaining the'coating of graphite thereon, and .a rotatable shaft' secured to said element to effect operation thereof 2. In resistance control apparatus, the combination with-a circular element having a peripheral portion thereof coated with conductive material, said element having a centrally, located, depression connected with the periphery thereof by a passage, of a'soft. metallic connector located in" said passage and having a portion located within said depression and another portion electrically connected with said conductive coating and a conductive hub member rigidly secured tosaid circular element in a relation to main-, tain contact with said-connector. v

3. In resistance control apparatus, the combination with a circular element having desire to secure a. peripheral portion thereof coated with conductive material, sa'id conductive coating having its continuity interrupted at a given region, said element having a centrally located'annular depression connected with the periphery of the same by a'passage adjacent 1 the break in the continuity of said conductive coatin of a soft metallic connector. located in sai passage and having a' portion located within said annular depression and another portion electrically connected with said conductive coatin and a hub member rigidly secured to sai circular element in a relation to maintain contact with said connector;

4. In resistance control apparatus, the combination with a circular element having a peripheral portion thereof coated with conductive material said conductive coating having its continuity interrupted at, a given region, said" elementhaving a centrally located annularde ression connected with the peri hery-thereo by a vpassage adjacent therea in the continuity of said conductive coatin of a soft metallic connector located within said annular depression and another in sai passage and having a portioncoiled portion thereof, electricall connected'with said conductive coating,"t e'alxial. de; th of said depression being'less than-theaimIeX-Q- tent of the coiled portion of said coimector, a conductive hub to be rigidly secured to said I circular element and within, the coiled portion of said'connector, said hub having a flange to engage the coiled ortion of said connector, and said hub an said circular said bracket and means to 'electricall element'having associated parts to maintain v posltive compression contact between sald I sulator, of a, support therefor comprising an insulating base having an "offset bracket tweensaid base and said bracket, said base and bracket having aligned-openings to receive the projecting portions of said hub, said bracket comprising resilient'material to provide axial pressure upon said insulator and hub.

6. In resistance controL apparatus, the combination with a circular insulator having the periphery thereof coatedwith conductive material,.- the periphery of said insulator being interrupted at a given region,.a conductive hub centrally located in said insulator, a rotatable operating shaft secured to said' hub, a, Soft metallic connector electrically connecting the peripheral conductive material with said hub member and a clamping support for said insulator comprising a resilient conductive bracket toengage and provide a terminal of said hub member. a

l 7. The combination) with an insulatingbase, a' resilient conductive clamping bracket secured thereto, a resistance element to be '75 secured thereto to receive said insulator be- 1 inserted and retained between said base and c said 'bracketQand means to electrically connect the resistor of said resistance element with said bracket, of a terminal support carried by said bracket for securemen'tand electrical connection of anassociated control instrumentalit 8; The com ination with an insulating base, a resilientconductive clamping bracket secured thereto, a resistance element to be inserted and retained between said base'and said bracket and means to electrically connect the resistor of said resistance element with said bracket; of a co-operating contactor for said resistance element, a conductive contactor support carried by said base, and auxiliary supporting terminals carried by said support and said bracket.

9. The combination withi an insulating base, a resilient conductive clamping bracket secured thereto, a resistance element to be inserted and retained between sa d base and connect the resistor of said resistance e ement T'with said bracket,'o'fa co-operating contactor for said resistance element,.a conductive contactor support carried by said base and ment and electrical connection of an associated control instrumentality. A 1 0. The combination with an nsulating base, a resilient conductive clamping bracket secured thereto, a resistance element to be inserted and retained between said base and said bracket and means to electrically connect the resistor of said resistance element with said bracket, of a co-opcrating contactor for said resistance element, a conductive cont-actor support carried by said base and relatively adjustable, terminals carried by said support and said bracket to. provide for mechanical securement and electrical connection of an associated control instrumentality.

11. The combination with an insulating base, a resilient conducti e clamping: bracket secured thereto, a resistance element to be inserted and retained between said base and said bracket and means to electrically'connect the resistor of said resistance element with said bracket, of a co-operating contactor for said resistance element, a conductive contactor support carried by said base, terminals carried by said support and said bracket to provide for mechanical securement and elec trical connection of an associated control instrumentality, and means comprising a pivotally and slidably adjustable slotted link to secure certain of said terminals to its associated support.

12. The combination with an insulating base, a resilient conductive clamping bracket secured thereto, a resistance element to be inserted and retained between said base and said bracket and means to electrically connect the resistor of said resistance element with said bracket, of a co-operating contactor for said resistance element, a conductive contactor support carried by said base, terminals carried by said supportand said bracket to provide for mechanical securement and electrical connection of an associated control instrumentality, and means comprising a slotted link connecting said bracket with its associated terminal and slidably and pivotally adjustable relatively to each.

13. The combination with an insulating base, a resilient conductive clamping bracket secured thereto, a resistance element to be inserted and retained between said base and said bracket and means to electrically con-.

nect the resistor of said resistance element with said bracket, of a co-operating contactor for said resistance element, a conductive contactor support carried by said base, auxiliary supporting terminals carried by said support and said bracket, and a conductive supporting element secured to said base in contact with said bracket.

In witness whereof I have hereunto subscribed my name.

HENRY J. 'WIEGAND. 

